View Full Version : Nitro woes
06-03-2006, 01:50 AM
I know this is an electric forum, that's why I put this in off topic. I went out to the field today with my House of Balsa Spacewalker to run it and fly it for the first time. I had bought it off another club member last fall, with an OS .10 LA engine on it. All I needed to do to it was put a reciever in it.
Well, I couldn't get it to stay running. It ran for awhile once, but wouldn't really go to full throttle, it choke at about half throttle.
Now I have a sticky messy plane that I really like. I would convert to electric, but it's already got the engine on it and I would really like to learn how to run glow engines. I have no experience with them. Does anyone here have any advice? (Besides the all too common 'glow is evil, go electric' comments) It's really frustrating.
06-03-2006, 02:36 AM
How 'bout too lean? Most guys lean out the engine until it is just screaming: wrong. Lean it out until it JUST runs on 2-stroke, then launch. Lean engines = expensive, they burn up. Rich engines last a long, long time.
Sorry, I know this is a fuel post, but this guy needs to save that engine so that he can sell it and buy an electric motor...
06-03-2006, 05:01 PM
If you have a tach, it's fairly easy to set it to the correct running speed to preserve your motor:
1. Set your high-speed needle valve to running "sloppy rich" at full throttle.
2. Lean out the needle until the motor won't go any faster according to your tach.
3. Now richen it back up to around 500RPM below peak (for a new engine), or 200-300RPM below peak (for a broken-in engine).
Of course, now you have to get your idle set up right, if it's not idling right. That one's a bit more tricky, so I won't offer any advice as I suck at it :)
06-03-2006, 05:43 PM
We have a VAX 6000 cluster at work
Did you get a manual? there are very specific instructions for tuning that include tuning the low speed needle valve. I have tried to ignore these instructions and have paid dearly. Here is a brief summary:
1. Get your full throttle setting set.
2. Lift the model at a 45 degree noseup angle and make sure it doesn't lean out and quit. If it does open the valve and keep trying till you can lift the nose and have it stay running.
3. Reduce throttle halfway and pinch the fuel line going to the carb. if the mixture is rich the engine will speed up. close the low speed needle valve a quarter of a turn. that's the one buried in the throttle lever that you need a screww driver to adjust.
If it just quits then open the low speed valve, you don't want to be too lean.
5. keep reducing the throttle a little more and re adjusting as you go along. Evetually you want to get to a nice idle where pinching the line has no effect to rpm but will of course make the engine quit.
This is a pain in the neck since you have to stop and start te engine a lot. But it is worth it.
Yes this will fix your mid range throttle response problem. You probably won't have to do this again for a very long time.
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